INFO: task syz-executor5:8468 blocked for more than 120 seconds.
      Not tainted 4.9.70-gc14c7b3 #110
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29184  8468   3536 0x00000004
 ffff8801d00c0000 ffff8801d895c540 ffff8801d895c540 ffff8801cec0e000
 ffff8801db221458 ffff8801ce5df740 ffffffff83898c3b ffff8801ce5df718
 ffffffff8123886f 00ffffff838a45aa ffff8801db221d28 ffff8801db221d50
Call Trace:
 [<ffffffff8389a1df>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a46c0>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc3dd8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a3442>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a3442>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8200aa35>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
 [<ffffffff8200b8e1>] tty_mode_ioctl+0x931/0x9c0 drivers/tty/tty_ioctl.c:970
 [<ffffffff8200ba10>] n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:1161
 [<ffffffff81fff5d8>] n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2437
 [<ffffffff81ff8413>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aaa0a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aaa0a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815aba2f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815aba2f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838aa405>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff812355e0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3306:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff820022a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor5/8468:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff8200aa35>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8907d00 ffffffff81d90c49 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810ba1a0 ffff8801d8907d38
 ffffffff81d9bd6d 0000000000000000 0000000000000000 ffff8801d05a8418
Call Trace:
 [<ffffffff81d90c49>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d90c49>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9bd6d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9bea7>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba294>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81370410>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81370410>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81370410>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81370410>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838aa6aa>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8435 Comm: syz-executor5 Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cec0e000 task.stack: ffff8801d1a58000
RIP: 0010:[<ffffffff813681fb>] 
c [<ffffffff813681fb>] __sanitizer_cov_trace_pc+0x2b/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801d1a5fb28  EFLAGS: 00000246
RAX: ffff8801cec0e000 RBX: ffffc900054d6060 RCX: ffffffff81fff6f6
RDX: 0000000000000002 RSI: ffffc9000198e000 RDI: ffffc900054d7260
RBP: ffff8801d1a5fb28 R08: 1ffff10039d81d1a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801cec0e000 R12: ffffc900054d5000
R13: 000000077f67f31b R14: 0000000020feb000 R15: ffff8801da3b2cb8
FS:  00007f65416ae700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd8085089b8 CR3: 00000001d54bf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d1a5fb78
c ffffffff81fff6f6
c ffffffffffffffff
c 000000000000031b
c
 0000000000000000
c ffff8801da3b2a80
c 1ffff1003a34bf75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801cfa95000
c ffff8801d1a5fd70
c ffffffff81ff8413
c
Call Trace:
 [<ffffffff81fff6f6>] inq_canon drivers/tty/n_tty.c:2414 [inline]
 [<ffffffff81fff6f6>] n_tty_ioctl+0x266/0x2d0 drivers/tty/n_tty.c:2431
 [<ffffffff81ff8413>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aaa0a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aaa0a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815aba2f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815aba2f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838aa405>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
c55 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
c40 
c55 
c01 
c00 
c65 
c8b 
c15 
cec 
cd2 
cca 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c4d 
c08 
c75 
c2b 
c8b 
c90 
c68 
c12 
c00 
c00 
c83 
cfa 
c02 
c75 
c20 
c<48> 
c8b 
cb0 
c70 
c12 
c00 
c00 
c8b 
c80 
c6c 
c12 
c00 
c00 
c48 
c8b 
c16 
c48 
c83 
cc2 
c01 
c48 
c